1. Field of the Invention
The present invention relates to an engine-rotation detecting system including a detected portion provided on a rotary shaft of an engine, and a sensor for detecting the position of the detected portion.
2. Description of the Related Art
A detecting system for detecting a crank angle of an engine is conventionally known from Japanese Utility Model Application Laid-open No. 62-26566, which includes a detected portion projectingly provided on an outer periphery of a rotatable plate mounted on a crankshaft, and a sensor disposed in the vicinity of the rotatable plate for detecting the position of the detected portion.
In general, the rotatable plate for detecting the rotation is conventionally provided separately from a thrust limiting plate for limiting the axial movement of the rotary shaft of the engine, resulting in an increased number of parts due to the rotatable plate. In addition, the position of the rotatable plate is spaced apart from the position of the thrust limiting plate and for this reason, there is a possibility that the position of the rotatable plate may be varied by an influence of the thermal expansion of the rotary shaft or the like, resulting in a reduced detection accuracy of the sensor.